Field of the Invention
The invention relates to a semiconductor array with self-adjusted contacts and a method for its production.
A semiconductor array with self-adjusted contacts is known from U.S. Pat. No. 4,729,969. The semiconductor array shown therein is distinguished by an electrode or contact surface that extends not only above a doped region to be contacted but also above an insulated region adjoining the doped region. The contact hole is offset from the doped regions above the insulated region. The result attained is that when there are two doped regions to be contacted, which are adjacent one another in a first lateral direction and one of which has a contact surface of the type described and another has a contact surface of the usual type that is merely disposed above the doped region, the doped regions can be positioned as close together as possible yet without failing to observe a minimum spacing between the respective contacts. One of the two contacts is then in fact disposed offset from the corresponding doped region in the direction remote from the other contact, above the corresponding insulated region.
The method described therein has the disadvantage of not attaining the desired success when there are more than two doped regions adjacent one another in a first lateral direction that are to be contacted, namely that a plurality of adjacent doped regions be spaced as close as possible to one another. If in fact the minimum spacing between two corresponding contacts is not to be undershot, then all that can be done in the way described is to decrease the spacing of the two corresponding doped regions. Conversely, their spacing from other doped regions adjacent them must even be increased, on the condition that the dimensions of the doped regions in the first lateral direction are not increased, and the same minimum spacings are adhered to between all of the contacts. The proposed structure of the contact surfaces thus does not make it possible, given an allowable minimum spacing between the doped regions, to place the doped regions and insulated regions in a regular structure.
That problem becomes even worse if, as proposed in U.S. Pat. No. 4,729,969, both contacts of two adjacent doped regions are each offset in opposite directions from the doped regions. Admittedly that does make it possible for two affected doped regions to be brought closer together, with the same minimum spacing between the contacts. Nevertheless, that can be done only at the expense of the spacing of those doped regions from other doped regions adjacent them.